Stephen dudley field



UNITED STATES PATENT OFFICE.

STEPHEN DUDLEY FIELD, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT IN SCREW-POSTS FOR ELECTRICAL APPARATUS.

" Specification forming part of Letters Patent No. 140,618, dated July 8, 1873; application filed April 10, 1873.

To all whom it may concern:

, Be it known that I, STEPHENDUDLEY FIELD,

' of San Francisco city and county, State of California, have invented an Improved Binding-Screw Post for Electrical Purposes; and I do hereby declare the following description and accompanying drawings are sufiicient to enable any person skilled in the art or science to which it most nearly appertains, to make and use my said invention or improvement,

- which Figure 1 is a side elevation of my bindingpost. Fig. 2 is a sectional elevation. Fig. 3 is a horizontal section.

A represents the base; B, the vertical screwstem; and C, the set-nut or head of an ordinary screw-post, such as is at present in use.

Heretofore the end of the current-wire has been wrapped two or more times around the lower part of the vertical screw-stemv B, and the set-nut C has been turned down so as to bind the coil thus formed between the two opposing faces of the set-nut and base, and it frequently happens that when thus confined the coil becomes displaced, either by the turning of the set-nut to fasten it or otherwise, so that the contact is imperfect, thus impairing the working of the machine.

My improvement consists in drilling a hole, t, through the base of the vertical screw-stem B directly upon a line with the horizontal face of the base A, so that the end of the currentwire can be passed through the hole and the set-nut turned down uponit, so as to secure it. By this means the liability of displacement, so as to afiect the electric current is avoided, as the wire will always be in contact with the post, and the turning of the face of the setscrew down upon the wire will polish the wire and give an excellent electrical contact.

The device is also much more simple and more A easily managed than the ordinary arrangement.

Having thus described my invention, whatI claim, and desire to secure by Letters Patent, 1s

Abindingscrew post for electrical purposes, composed of the base A, set-screw C, and screw-stem B having the perforation i in its base, substantially as and for the purpose above described.

In witness whereof I hereunto set my hand andseal.

STEPHEN DUDLEY FIELD. [L. s]

Witnesses:

JOHN L. Rooms, 0. M. RICHARDSON. 

